Messages in this thread Patch in this message | | | From | Masami Hiramatsu <> | Subject | [PATCH 3/3] x86/insn-eval: Fix not using prefixes.nbytes for loop over prefixes.bytes | Date | Wed, 2 Dec 2020 17:51:27 +0900 |
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Since the insn.prefixes.nbytes can be bigger than the size of insn.prefixes.bytes[] when a same prefix is repeated, we have to check whether the insn.prefixes.bytes[i] != 0 and i < 4 instead of insn.prefixes.nbytes.
Fixes: 32d0b95300db ("x86/insn-eval: Add utility functions to get segment selector") Cc: stable@vger.kernel.org Reported-by: Kees Cook <keescook@chromium.org> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> --- arch/x86/lib/insn-eval.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c index 58f7fb95c7f4..c52c91461f52 100644 --- a/arch/x86/lib/insn-eval.c +++ b/arch/x86/lib/insn-eval.c @@ -67,7 +67,7 @@ bool insn_has_rep_prefix(struct insn *insn) insn_get_prefixes(insn); - for (i = 0; i < insn->prefixes.nbytes; i++) { + for (i = 0; insn->prefixes.bytes[i] && i < 4; i++) { insn_byte_t p = insn->prefixes.bytes[i]; if (p == 0xf2 || p == 0xf3) @@ -99,7 +99,7 @@ static int get_seg_reg_override_idx(struct insn *insn) insn_get_prefixes(insn); /* Look for any segment override prefixes. */ - for (i = 0; i < insn->prefixes.nbytes; i++) { + for (i = 0; insn->prefixes.bytes[i] && i < 4; i++) { insn_attr_t attr; attr = inat_get_opcode_attribute(insn->prefixes.bytes[i]);
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